1. Field of the Invention
The invention relates to a drive for a folder of a rotary printing machine having rotating subassemblies that can be driven, in particular a cutting cylinder, a pin folding blade cylinder, a folding jaw cylinder, a gripper folding blade cylinder, and perforating cylinders belonging to a perforating device.
2. Description of the Related Art
U.S. Pat. No. 5,242,367 discloses a folder whose synchronism between the parts is brought about by pairs of gears which are in each case coupled coaxially to one another, the pairs of gears being separated from one another by means of clutches and the pairs of gears being displaced axially for the purpose of changing over the fold or setting the format, in particular adjusting the prefold.
This solution is technically complicated, requires a relatively great amount of space and, because of multiple tooth engagements, is afflicted by rotational play and threatened by wear.
U.S. Pat. No. 5,676,630 discloses a folder with format changing in which cylinder segments of the folding cylinders are rotated with respect to one another by means of two epicyclic gear mechanisms which can be adjusted in relation to each other for the purpose of changing the format.
This solution is technically complicated and, because of multiple tooth engagement, is afflicted by rotational play and threatened by wear.
DE 197 55 428 A1 shows an apparatus for adjusting the folding mechanisms on a folding cylinder of a folder, the adjustment of the cylinder elements bearing folding mechanisms being carried out with two harmonic drive mechanisms in each case connected to the cylinder elements.
The disadvantage is that the drive to the folder is not configured in a low-oscillation manner, and no influence can be exerted on the oscillations which occur.
U.S. Pat. No. 5,901,647 shows a method for the low-oscillation driving of rotating components of a folder, and a low-oscillation folder drive, in each case a motor being assigned to each rotating component, such as perforating rolls, folding jaw cylinders or longitudinal folding devices, and being connected by a form fit to the respective component.
The disadvantage is that in order to adjust the cylinder parts of each cylinder, additional mechanical elements are necessary and, in the event of failure of a motor, the control of the folder initiates a rapid stop for all the rotating subassemblies and the capping of the paper web running into the folder.
The invention is based on the object of providing a low-wear, space-saving and low-oscillation drive for a folder with changeable format, the intention being to continue to operate the folder without functional impairment in the event of failure of a motor.
This object is fulfilled by splitting up the drive of the folder into a plurality of subsystems wherein each subsystem is assigned a controlled position drive motor.
A particular advantage of the invention is that, as a result of the use of individual controlled-position drive motors on the respective function groups of the folder, such as individual drive motors on the knife cylinder, on the pin folding cylinder, on the folding jaw cylinder and on the perforating device, it is possible for the drive of a folder to be divided up into a plurality of subsystems whose drives are separated from one another.
In addition, as a result of this subdivision of the drive of a folder into a plurality of subsystems whose drives are separated from one another, the transmission of oscillations between the subsystems is minimized.
A further advantage is that the subsystems can be coupled to one another via switchable clutches.
In the event of failure of one of the drive motors, this advantageously permits further operation of the subsystem in which the drive motor has failed, by coupling this xe2x80x9cdrive-lessxe2x80x9d subsystem to at least one of the other subsystems, and therefore the serviceability of the entire folder is ensured.
Furthermore, if there is a requirement for a higher torque, for example if there is a requirement for a higher starting torque on the knife cylinder, the subsystems can optionally be coupled to one another via the clutches.
It is advantageous that the individual controlled-position drive motors are used for adjustment functions, such as prefold adjustment or changing over to other types of fold, for example changing over from parallel fold to delta fold or to Z fold and vice versa. It is therefore possible for the mechanical actuating devices providing these adjustment functions for format changing or fold adjustment to be dispensed with.
Furthermore, as a result of the use of the drive motors configured as individual drives, a division of the power in the drive can be carried out, as a result smaller drive motors can be used, which also reduces the dimensioning of the controlled electronics in a corresponding way.
It is significant that, as a result of the use of the individual drives and the subdivision of the mechanical drive train into functional groups, it is possible to exert an active influence on the dynamic system as a folder or as a folding unit via the controlled electronics of the drives. If a plurality of drive motors are used, these can be arranged in the folder in such a way that oscillations which occur are counteracted on the basis of the beneficial, that is to say oscillation-reducing, arrangement of the drive motors in the folder, as a result of which oscillation amplitudes are minimized. Likewise, fold deviations because of oscillations are minimized. Moreover, the oscillations that impair the folding quality are counteracted by the drive control of the motors.
It should also be mentioned that, during steady state operation, all the subsystems can be coupled together and, in this way, by means of defined subdivision of the total drive torque, the gear train consisting of the individual gears engaged with one another is braced. As a result, the multiple tooth engagement in the individual subsystems and in the overall drive train of the folder is no longer subject to rotational play and threatened by wear in steady state operation.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.